Tube for a tire

ABSTRACT

A tube tire capable of simply, positively preventing the generation of a puncture due to contact of opposing portions of the wall surface of a tube. Double wall portions are formed at rim striking portions of a tube contained in a tire, and the internal spaces of the double wall portions are filled with a sealant. When the tire rides over an obstacle and the tire and the tube are clamped between the flange portions of a rim and the obstacle, the shock is damped by the double wall portions to prevent damage of the tube. Even if the double wall portions are damaged, the damaged portion is repaired with the sealant, thereby eliminating the generation of leakage of air.

This is a divisional of application Ser. No. 08/884,648, filed of Jun.27, 1997, now U.S. Pat. No. 6,158,489 the entire contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tube tire including a tire mountedaround the outer periphery of a rim and a tube contained in a spacedefined by the rim and the tire.

2. Description of Background Art

Tube tires, making use of the excellent airtightness of tubes, aregenerally mounted on wheels with wire spokes which are extensively usedfor motorcycles or bicycles.

When a radial load is applied to a wheel mounted with a tube tire, thetire and the tube are deformed by the load, and in some cases,particularly in the case where the tire rides over a rigid obstacle suchas a rock or the vehicle is jumped and grounded upon off-road operation,there occurs a rim striking phenomenon in which the tube is forciblyclamped between the largely deformed tire and a metal made rim andthereby opposing areas of the inner wall surface of the tube are broughtin press-contact with each other. When the opposing areas of the innerwall surface of the tube are brought in press-contact with each other bysuch a rim striking phenomenon, there often occurs a so called shockpuncture in which the press-contact portion is pierced. In particular,as the opposing areas of the wall surface of the tube are inpress-contact with each other, a portion near the rim (hereinafter,referred to as “a rim striking portion”) is applied with a local loadfrom the metal rim. A

A tube tire to avoid such an inconvenience has been proposed in JapanesePatent Laid-open No. Hei 5-201213, in which a damper formed in acrescent-shape in cross section is interposed between the inner surfaceof a tread portion of the tire and the outer surface of the tube forpreventing damage to the tube due to the rim striking phenomenon by thedamper.

The above-described tube tire has a problem wherein since a damper isprovided in addition to other elements, the number of parts isincreased, to thereby increase the weight of the tire as well as themanufacturing cost.

In view of the foregoing, the present invention has been made, and anobject of the present invention is to provide a tube tire capable ofsimply, effectively preventing the generation of a puncture due tocontact of opposing portions of the wall surface of the tube.

In the above-described tube tire, however, the tube, when pierced by anail or the like penetrating the buffer, is unavoidably punctured, andfurther, since the buffer is additionally provided, the number of partsis increased, to thereby increase the weight of the tire as well as themanufacturing cost.

In view of the foregoing, the present invention provides a tube tirecapable of simply, effectively preventing the generation of a puncturedue to a pierced damage to a tube by a nail or the like and of shockpuncture due to riding of the tire over an obstacle.

To achieve the above object, according to the present invention there isprovided a tube tire including a tire mounted around the outer peripheryof a rim and a tube contained in a space defined by the rim and thetire. A double wall portion is provided at a rim striking portion of thetube, the rim striking portion is a portion brought in press-contactwith the rim while putting the tire therebetween when a radial load isapplied to the tire.

According to the present invention, a tube tire is provided wherein thedouble wall portion is a hollow structure.

According to the present invention, a tube tire is provided wherein thedouble wall portion has an internal space which is filled with asealant.

According to the present invention, a tube tire is provided wherein thedouble wall portion is formed by sticking a rubber sheet on the outersurface of the tube.

To achieve the above object, a tube tire is provided which includes atire mounted around the outer periphery of a rim and a tube contained ina space defined by the rim and the tire. The tube includes a peripheralwall formed in a circular shape in cross section wherein the interior ofthe peripheral wall is partitioned by an outer bulkhead and an innerbulkhead so that an outer sealant chamber to be filled with a sealant isdefined by an outer peripheral wall constituting an outer halfcircumference of the peripheral wall and the outer bulkhead. An innersealant chamber to be filled with the sealant is defined by an innerperipheral wall constituting an inner half circumference of theperipheral wall and the inner bulkhead, and an air chamber to be filledwith an air is defined between the outer bulkhead and the innerbulkhead.

According to the present invention, a tube tire is provided wherein thetube integrally includes the peripheral wall, the outer bulkhead and theinner bulkhead which are formed by extrusion molding.

To achieve the above object, a tube tire includes a tire mounted aroundthe outer periphery of a rim and a tube contained in a space defined bythe rim and the tire. The tube includes a peripheral wall formed in acircular shape in cross section wherein the interior of the peripheralwall is partitioned by a bulkhead so that an air chamber to be filledwith air is defined between an air chamber side peripheral wallconstituting a half circumference of the peripheral wall and thebulkhead and a sealant chamber to be filled with a sealant is definedbetween a sealant chamber side peripheral wall constituting theremaining half circumference of the peripheral wall and the bulkhead. Abuffer is interposed between the outer surface of the tube and the innersurface of the tire.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a transverse sectional view of a wheel mounted with a tubetire;

FIG. 2 is a flow chart illustrating steps for manufacturing a tube;

FIG. 3 is a schematic view illustrating the function of a tube of thepresent invention;

FIG. 4 is a view, similar to FIG. 1, showing a second embodiment;

FIG. 5 is a view, similar to FIG. 1, showing a third embodiment.

FIG. 6 is a transverse sectional view of a wheel mounted with a tubetire;

FIG. 7 is a flow chart illustrating steps for manufacturing a tube;

FIG. 8 is a schematic view illustrating the function of the tube tire ofthe present invention;

FIG. 9 is a transverse sectional view of a wheel mounted with a tubetire;

FIG. 10 is a flow chart illustrating steps for manufacturing a tube;

FIG. 11 is a schematic view illustrating the function of the tire tubeof the present invention; and

FIGS. 12(a) to 12(c) are views illustrating a sectional expansion ratioof the tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the accompanying drawings.

A rim R, to be mounted on a wheel used for a motorcycle, is connected toa hub (not shown) via wire spokes S. A tube tire T composed of a tire 1and a tube 2 contained in the tire 1 is mounted on the rim R. Tube 2 hasan inner radius Ri, a central radius Rc, and an outer radius Ro. Thetube 2 has a peripheral wall 4 formed in an annular shape incross-section, and the peripheral wall 4 is composed of an air chamberside peripheral wall 4 i positioned radially inwardly and a sealantchamber side peripheral wall 4 o positioned radially outwardly. A pairof connection portions for connecting the air chamber side peripheralwall 4 i of the peripheral wall 4 to the sealant chamber side peripheralwall 4O thereof are connected to each other by a bulkhead 5 formedintegrally therewith. A pair of double wall portions 4 d, 4 d, eachbeing formed in a hollow shape, are provided at rim striking portions ofthe air chamber side peripheral wall 4 i that is, portions of the airchamber side peripheral wall 4 i to be brought in press-contact with therim R while putting the tire 1 therebetween when a radial load isapplied to the tire 1.

An air chamber 3 formed in an approximately circular shape in crosssection, which is defined by the air chamber side peripheral wall 4 iand the bulkhead 5, is filled with air. A sealant chamber 7, formed inan approximately arcuate shape in cross section, is defined by thesealant chamber side peripheral wall 4 o and the bulkhead 5 and isfilled with a known liquid sealant. Each of the internal spaces of apair of the double wall portions 4 d, 4 d is also filled with a knownliquid sealant.

The rim R includes an annular rim main body 11 extending in thecircumferential direction of the tube tire T and a pair of flangeportions 12, 12 extending radially outwardly from both the radial endsof the rim main body 11 and holding the inner periphery of the tire 1.An air valve 6 for filling the air chamber 3 with air is formed in thetube 2 and passes through an air valve mounting portion 13 formed at aposition in the circumferential direction of the rim main body 11 and isfixed by nuts 14, 15.

Since the sealant chamber 7 of the tube 2 is held in a shape followingthe inner surface of the tire 1 by air pressure within the air chamber3, the sealant 8 filled in the sealant chamber 7 can be prevented frombeing shifted on the outer peripheral side of the tube 2 even when thesealant 8 is applied with a centrifugal force due to the rotation of thewheel. Accordingly, even when the tube 2 is pierced with a nail or thelike in the radial or sideward direction, the pieced portion isimmediately buried with the sealant 8 to be thus repaired, so that it ispossible to retard the leakage of air from the air chamber 3.Additionally, since the sealant 8 is held in the sealant chamber 7 andis not allowed to flow on the air chamber 3 side, it does not block theair valve 6 or a pressure gauge touched with the air valve 6.

Next, a process of manufacturing the tube 2 will be described.

As shown in FIG. 2, the tube 2 is manufactured in accordance withmanufacturing steps including a material kneading step, a tube materialextrusion molding step, a cutting step, an air valve mounting step, apiecing step, a joining step, a first vulcanizing step, a sealantfilling step, a raw rubber sheet sticking step, a second vulcanizingstep, and an inspection step.

First, a raw rubber is kneaded at the material kneading step and isextrusion-molded at the tube material extrusion molding step, to form atube material 2′ made of the raw rubber. The tube material 2′ iscontinuously extrusion-molded from a nozzle of an extrusion moldingmachine and includes a peripheral wall 4 formed in a circular shape in atransverse cross section and a bulkhead 5 connecting two pointspositioned along the diameter of the peripheral wall 4. The peripheralwall 4 is divided into an air chamber side peripheral wall 4 i and asealant chamber side peripheral wall 40 with respect to the portionsconnected to the bulkhead 5, and a pair of double wall portions 4 d, 4 dare integrally formed on the air chamber side peripheral wall 4 i.

The tube material 2′ is cut into a specified length at the subsequentcutting step, and an air valve 6 is mounted at a suitable position ofthe air chamber side peripheral wall 4 i at the air valve mounting step.And, at the piercing step, the sealant chamber side peripheral wall 40of the tube material 2′ and the outer walls of the double wall portions4 d, 4 d are pierced to form sealant filling holes 4 ₁, . . . , 4 ₁.

Both the end portions of the tube material 2′ are joined to each otherat the subsequent joining step, and at the first vulcanizing step, thetube material 2′ is inserted in a heating die, and the air chamber sideperipheral wall 4 i and the sealant chamber side peripheral chamber 40are brought in close-contact with the heating die and the bulkhead 5 isalso brought in close-contact with the sealant chamber side peripheralwall 40 by supplying a heated air or a high temperature steam into theair chamber 3 from the air valve 6. In such a state, vulcanization isperformed by heating the heating die.

At the subsequent sealant filling step, the sealant 8 is supplied fromthe sealant filling holes 4 ₁, . . . , 4 ₁ to fill the sealant chamber 7and the internal spaces of the double wall portions 4 d, 4 d. At thistime, by expanding the air chamber 3 by the supply of air from the airvalve 6 prior to the filling of the sealant 8, the bulkhead 5 is broughtin close-contact with the sealant chamber side peripheral wall 40 toperfectly discharge the air in the sealant chamber 7 and the inner wallsof the double wall portions 4 d, 4 d are brought in close-contact withthe outer walls thereof to perfectly discharge the air in the internalspaces thereof. In such a state, the filling of the sealant 8 isstarted. The starting of the filling of the sealant 8 in the state thatthe air in the sealant chamber 7 and the internal spaces of the doublewall portions 4 d, 4 d is perfectly discharged, it is possible toeffectively prevent the entrapment of the air in the sealant 8 and henceto fill the sealant chamber 7 and the internal spaces of the double wallportions 4 d, 4 d with only the sealant 8. Additionally, since the airis supplied into the air chamber 3 using the air valve 6, it is possibleto eliminate the need for the provision of an air filling hole in theair chamber side peripheral wall 4 i.

A raw rubber sheet 19 is stuck on the peripheral wall 4 so as to coverthe sealant filling holes 4 ₁, . . . , 4 ₁ at the raw rubber sheetsticking step, and then the sealant filling holes 4 ₁, . . . , 4 ₁ areblocked by local vulcanization of the vicinity of the raw rubber sheet19 at the second vulcanization step, to finish the tube 2. Since thesealant filling holes 4 ₁, . . . , 4 ₁ are blocked using the raw rubbersheet 19 being the same material as that of the tube material 2′, it ispossible to improve the strength of the blocking portion, and hence toeffectively prevent the leakage of the sealant 8. Thus, the finishedtube 2 is inspected at the inspection step, to complete themanufacturing steps.

Next, the function of the first embodiment will be described. As shownin FIG. 3, when the tube tire T rides over an obstacle 20 on a roadsurface and is applied with a shock load, part of the tire 1 and thetube 2 are compressed in the radial direction by the load. At this time,the tire 1 and the tube 2 are clamped between the flange portions 12, 12of the rim R projecting radially outwardly and the obstacle 20, so thatthe opposing portions of the inner wall surface of the tube 2 arebrought in press-contact with each other. However, since the rimstriking portions of the tube 2, which are most susceptible to damages,are provided with the double wall portions 4 d, 4 d, the thickness ofthe tube 2 is increased at these portions. This makes it possible toeffectively prevent damage of the tube 2 due to the rim strikingphenomenon.

Furthermore, since the internal spaces of the double wall portions 4 d,4 d are filled with the sealant 8, they are compressed in the vicinityof the ground portion of the tire 1, it is possible to furthereffectively prevent damage of the tube 2 due the rim striking phenomenonby a shock absorbing effect of the sealant 8 generated when it is movedupwardly. Additionally, even if the double wall portions 4 d, 4 d aredamaged by the rim striking phenomenon, the sealant 8 filled in theinternal spaces acts to bury the damaged portion so as to repair it,thereby retarding the leakage of the air from the air chamber 3.

Accordingly, with a simple structure in which the double wall portions 4d, 4 d are formed at the rim striking portions of the tube 2 and theinternal spaces thereof are filled with the sealant 8, it is possible toavoid the generation of the shock puncture, without a large increase inweight as well as a large increase in manufacturing cost of the tubetire T.

A second embodiment of the present invention will be described withreference to FIG. 4. In a tube 2 in the second embodiment, each ofdouble wall portions 4 d, 4 d is a simple double layer having nointernal spaces and not being filled with a sealant 8. According to thisembodiment, the effect of preventing damage of the tube 2 by the sealant8 cannot be obtained. However, since the thickness of the tube 2 isincreased at the double wall portions 4 d, 4 d, it is possible toprevent damage of the tube 2 due to the rim striking phenomenon. Also,if the thickness of the rim striking portion is simply increased, thestep portion where the thickness is changed receives stressconcentration and is easily cracked. However, in this embodiment, sincethe rim striking portions are provided with the double wall portions 4d, 4 d, the outer and inner walls of the double wall portions 4 d arerelatively movable and are thereby increased in flexibility, so that itis possible to relax the stress concentration, and hence to prevent thegeneration of cracking.

A third embodiment will be described with reference to FIG. 5. In a tube2 in the third embodiment, raw rubber sheets 21, 21 are each joined onthe outer surfaces of the rim striking portions of the tube 2, to formdouble wall portions 4 d. The raw rubber sheets 21, 21 are each joinedon the tube 2 prior to the first vulcanization step of the manufacturingsteps shown in FIG. 2, that is, when the tube material 2′ is in a rawrubber state, and are integrated with the tube material 2′ at the firstvulcanization step. In the third embodiment, the rim striking portionsof the tube 2 are reinforced by the raw rubber sheets 21, 21, so that itis possible to effectively prevent the generation of shock puncture.Furthermore, the double wall portions 4 d, 4 d can be simply providedonly by sticking the raw rubber sheets 21, 21 on the existing tube 2.

For example, in the embodiments, the tube 2 having the sealant chamber 7filled with the sealant 8 has been exemplified. However, the presentinvention is applicable to the tube 2 without any sealant chamber 7.

According to the present invention, since double wall portions areprovided at rim striking portions of a tube, which are brought inpress-contact with a rim while putting a tire therebetween when a radialload is applied to the tire, it is possible to effectively preventdamage and thereby the puncture of the tube which is forcibly clampedbetween the tire applied with a large load and the rim. If the tube isdamaged, since the boundary between the double wall portions is cracked,the possibility of breakage of the air chamber side peripheral wall canbe reduced. Furthermore, such effect can be obtained with a simplestructure in which only the double wall portions are formed at parts ofthe tube, to thereby suppress an increase in weight as well as inmanufacturing cost as compared with the conventional tube.

According to the present invention, since each of the double wallportions is a hollow structure, it is possible to relax the stressconcentration by the increased flexibility of the double wall portions,and hence to further effectively prevent damage to the tube.

According to the present invention, since the internal spaces of thedouble wall portions are filled with a sealant, if the double wallportions are damaged the damaged portion is repaired with the sealant,resulting in the increased durability of the tube.

According to the present invention, since the double wall portions areeach formed by sticking raw rubber sheets on the outer surface of thetube, it is possible to enhance the strength of the tube by the doublewall portions and prevent the generation of shock puncture, and toprovide the double wall portions with a simple structure in which onlythe rubber sheet is stuck on the existing tube.

Hereinafter, a fourth preferred embodiment of the present invention willbe described with reference to FIGS. 6-8.

As shown in FIG. 6, a rim R to be mounted on a wheel used for amotorcycle is connected to a hub (not shown) via wire spokes S. A tubetire T composed of a tire 101 and a tube 102 contained in the tire 101is mounted on the rim R. The tube 102 has a peripheral wall 104 formedin an annular shape in cross section. The peripheral wall 104 iscomposed of an outer peripheral wall 104 o positioned radially outwardand an inner peripheral wall 104 i positioned radially inward. A pair ofconnection portions for connecting the outer peripheral wall 104 o tothe inner peripheral wall 104 i are connected to each other by an outerbulkhead 105 o and an inner bulkhead 105 i formed integrally therewith.

An air chamber 103 filled with air is formed into an approximatelycircular shape in cross section and defined between the outer bulkhead105 o and the inner bulkhead 105 i. An outer sealant chamber 107 o isformed into an approximately arcuate shape in cross section and isdefined between the outer peripheral wall 104 o and the outer bulkhead105 o. An inner sealant chamber 107 i is formed into an approximatelyarcuate shape in cross section and is defined between the innerperipheral wall 104 i and the inner bulkhead 105 i. Each of the sealantchambers 107 o, 107 i is filled with a known liquid sealant 108.

The rim R includes an annular rim main body 111 extending in thecircumferential direction of the tube tire T and a pair of flangeportions 112, 112 extending radially outwardly from both the radial endsof the rim main body 111 for holding the inner periphery of the tire101. The base portion of an air valve 106 for filling the air chamber103 with air is formed in the tube 102 and is supported on a raw rubbermade air valve mounting portion 116 joined to pass through the innerperipheral wall 104 i and the inner bulkhead 105 i. The air valve 106passes through the air valve mounting portion 116 formed at a positionin the circumferential direction of the rim main body 111 and is fixedby nuts 114, 115.

Since the outer sealant chamber 107 o and the inner sealant chamber 107i of the tube 102 are held in shapes following the inner surface of thetire 101 by the air pressure of the air chamber 103, the sealant 108filled in each of the outer and inner sealant chambers 107 o, 107 i canbe prevented from being shifted on the outer peripheral side of the tube102 even when the sealant 108 is applied with a centrifugal force due tothe rotation of the wheel. As a result, even when the tube 102 ispierced with a nail or the like, the pieced portion is immediatelyburied with the sealant 108 to be thus repaired, so that the leakage ofair from the air chamber 103 can be retarded. Further, since the outerand inner sealant chambers 107 o, 107 i cover not only the outerperipheral side but also the inner peripheral side of the tube 102, evenwhen any portion of the tube 102 is pierced, the pierced portion can berepaired with the sealant 108. In addition, since the sealant 108 isheld in both the sealant chambers 107 o, 107 i and is not allowed toflow on the air chamber 103 side, it does not block the air valve 106 ora pressure gauge in contact with the air valve 106.

Next, a process of manufacturing the tube 102 will be described. Asshown in FIG. 7, the tube 102 is manufactured in accordance withmanufacturing steps including a material kneading step, a tube materialextrusion molding step, a cutting step, an air valve mounting step, apiecing step, a joining step, a first vulcanizing step, a sealantfilling step, a raw rubber sheet sticking step, a second vulcanizingstep, and an inspection step.

First, a raw rubber kneaded at the material kneading step isextrusion-molded at the tube material extrusion molding step, to form atube material 102′ made of the raw rubber. The tube material 102′ iscontinuously extrusion-molded from a nozzle of an extrusion moldingmachine includes a peripheral wall 104 formed in a circular shape intransverse cross section and an outer bulkhead 105 o and an innerbulkhead 105 i connecting two points positioned along the diameter ofthe peripheral wall 104. The peripheral wall 104 is divided into anouter peripheral wall 104 o and an inner peripheral wall 104 i withrespect to the portions connected to both the bulkheads 105 o, 105 i.The tube material 102′ having a complex sectional shape can be easilymanufactured by such extrusion molding.

The tube material 102′ is cut into a specified length during asubsequent cutting step, and a raw rubber made air valve mountingportion 116 covering the base portion of an air valve 106 is joined insuch a manner as to pass through the inner peripheral wall 104 i and theouter peripheral wall 105 i at the air valve mounting step. At thepiercing step, the outer peripheral wall 104 o and the inner peripheralwall 104 i of the tube material 102′ are pierced to form sealant fillingholes 104 ₁, . . . , 104 ₁.

Both the end portions of the tube material 102′ are joined to each otherby a splicer at the subsequent joining step, and at the firstvulcanizing step, the tube material 102′ is inserted in a heating die,and the outer and the inner peripheral walls 104 o, 104 i are brought inclose-contact with the heating die and the outer and inner bulkheads 105o, 105 i are respectively brought in close-contact with the outer andinner peripheral walls 104 o, 104 i by supplying a heated air or a hightemperature steam into the air chamber 103 from the air valve 106. Insuch a state, vulcanization is performed by heating the heating die. Atthis time, the rubber made air valve mounting portion 116 covering thebase portion of the air valve 106 is perfectly integrated with the tubematerial 102′.

At the subsequent sealant filling step, the sealant 108 is supplied fromthe sealant filling holes 104 ₁, . . . , 104 ₁ to fill the outer andinner sealant chambers 107 o, 107 i. At this time, by expanding the airchamber 103 by supply of an air from the air valve 106 prior to thefilling of the sealant 108, the outer and inner bulkheads 105 o, 105 iare respectively brought in close-contact with the outer and innerperipheral walls 104 o, 104 i to perfectly discharge the air in theouter and inner sealant chambers 107 o, 107 i. In such a state, thefilling of the sealant 108 is started. The starting of the filling ofthe sealant 108 in the state that the air in both the sealant chambers107 o, 107 i is perfectly discharged, it is possible to effectivelyprevent the entrapment of the air in the sealant 108 and hence to fillthe sealant chambers 107 o, 107 i with only the sealant 108. Inaddition, since the air is supplied into the air chamber 103 using theair valve 106, it is possible to eliminate the need of the provision ofan air filling hole in the outer and inner peripheral walls 104 o, 104i.

Raw rubber sheets 119, 119. are stuck on the peripheral wall 104 so asto cover the sealant filling holes 104 ₁, . . . , 104 ₁ at the rawrubber sheet sticking step, and then the sealant filling holes 104 ₁, .. . , 104 ₁ are blocked by local vulcanization of the vicinity of theraw rubber sheets 119, 119 at the second vulcanization step, to finishthe tube 102. Since the sealant filling holes 104 ₁, . . . , 104 ₁ areblocked using the raw rubber sheets 119, 119 being the same material asthat of the tube material 102′, it is possible to improve the strengthof the blocking portion, and hence to effectively prevent the leakage ofthe sealant 108. Thus, the finished tube 102 is inspected at theinspection step, to complete the manufacturing steps.

Next, the function of the fourth embodiment will be described. As shownin FIG. 8, when the tube tire T rides over an obstacle 120 on a roadsurface and is applied with a shock load, part of the tire 101 and thetube 102 are compressed in the radial direction by the load. At thistime, the tire 101 and the tube 102 are clamped between the flangeportions 112, 112 of the rim R projecting radially outwardly from theobstacle 120, so that the opposing portions of the inner wall surface ofthe tube 102 are brought in press-contadt with each other. However,since the tube 102, clamped by the tire 101, has a sufficient wallthickness and elasticity due to the four-layered structure of the outerperipheral wall 104 o, outer bulkhead 105 o, inner bulkhead 105 i andinner peripheral wall 104 i, so that it is possible to effectivelyprevent damages of the tube 102 due to the rim striking the obstacle120.

Further, when the outer and inner sealant chambers 107 o, 107 i filledwith the sealant 108 are compressed in the vicinity of the groundportion of the tire 101, the sealant 108 exhibits a shock absorbingeffect while moving upwardly within the tube 102, to thereby furthereffectively prevent damages of the tube 102 due to rim striking.Additionally, even if the tube 102 is damaged by rim striking, thedamaged portion is repaired by the sealant 108 filled in the outer andinner sealant chambers 107 o, 107 i, so that the leakage of the air fromthe air chamber 103 can be prevented.

Accordingly, with such a simple structure in which the outer and innersealant chambers 107 o, 107 i are formed in the tube 102 and filled withthe sealant 108, it is possible to avoid the generation of a shockpuncture, without the largely increased weight as well as the largelyincreased manufacturing cost of the tube tire T.

According to the present invention, since the outer and inner sealantchambers filled with the sealant are defined so as to cover the entirecircumference of the tube, even when any portion of the tube is pierced,the pierced portion can be repaired with the sealant to prevent theleakage of air. Also, in the case where the tube is forcibly clamped bythe tire applied with a large load and the rim, since the tube has asufficient wall thickness and elasticity by the four layered structureof the outer peripheral wall, outer bulkhead, inner bulkhead, and innerperipheral wall, so that it is possible to effectively prevent damagesof the tube 102 due to rim striking. Even if the tube is damaged by rimstriking, the damaged portion can be repaired with the sealant. Inaddition, the simple structure, in which the outer and inner sealantchambers are formed in the tube and are filled with the sealant, doesnot increase the weight and the manufacturing cost.

According to the present invention, since the tube integrally includingthe outer and inner peripheral walls and the outer and inner bulkheadsare formed by extrusion molding, it is possible to easily manufacturethe tube.

A fifth embodiment of the present invention is illustrated in FIGS. 9 to11 wherein a tube tire T composed of a tire 201 and a tube 202 containedin the tire 201 is mounted on a rim R of a wheel for a motorcycle. Thetube 202 has a peripheral wall 204 formed in an annular shape in crosssection, and the peripheral wall 204 is composed of an air chamber sideperipheral wall 204 i positioned radially inwardly and a sealant chamberside peripheral wall 204 o positioned radially outwardly. A pair ofconnection portions for connecting the air chamber side peripheral wall204 i of the peripheral wall 204 to the sealant chamber side peripheralwall 204 o thereof are connected to each other by a bulkhead 205 formedintegrally therewith. An air chamber 203, formed into an approximatelycircular shape in cross section and defined between the air chamber sideperipheral wall 204 i and the bulkhead 205, is filled with air. Asealant chamber 207 is formed into an approximately arcuate shape incross section and defined between the sealant chamber side peripheralwall 204 o and the bulkhead 206 is filled with a known liquid sealant208.

The rim R includes an annular rim main body 211 extending in thecircumferential direction of the tube tire T and a pair of flangeportions 212, 212 extending radially outwardly from both the radial endsof the rim main body 211 and holding the inner periphery of the tire201. An air valve 206 for filling the air chamber 203 with air is formedin the tube 202 and passes through an air valve mounting portion 213formed at a position in the circumferential direction of the rim mainbody 211 and is fixed by nuts 214, 215.

A mousse 216 made of rubber foam or the like is interposed between theinner surface of the tire 201 and the outer surface of the tube 202. Themousse 216 mounted in the tire 201 is opened at a portion opposed to therim main body 211, and the tube 202 is mounted in the mousse 216 throughthe opening portion. The mousse 216 is formed to be thin at a portioncorresponding to a tread surface of the tire 201 and to be thick at theremaining portion, that is, a portion applied with a large load by rimstriking.

Since the sealant chamber 207 of the tube 202 is held in a shapefollowing the inner surface of the tire 201 by an air pressure of theair chamber 203, the sealant 208 filled in the sealant chamber 207 canbe prevented from being shifted on the outer peripheral side of the tube202 even when the sealant 208 is applied with a centrifugal force due tothe rotation of the wheel. Also, if the tire 201 is pierced with a nailor the like, the leading end of the nail or the like does not easilyreach the tube 202 by the presence of the mousse 216, to reduce thepossibility that the tube 202 is damaged by the nail or the like. Evenwhen the tube 202 is pierced with a nail or the like in the radial orsideward direction, the pieced portion is immediately buried with thesealant 208 to be thus repaired, so that the leakage of air from the airchamber 203 can be retarded. If the air in the air chamber 203 leaks dueto puncture of the tube 202, since the shape of the tire 201 can be keptsomewhat by the rigidity of the mousse 216, the operation of the vehiclecan be continued until a repair shop is located.

Additionally, since the sealant 208 is held in the sealant chamber 207and is not allowed to flow on the air chamber 203 side, it does notblock the air valve 206 or a pressure gauge connected to the air valve206.

A process of manufacturing the tube 202 will be described. As shown inFIG. 10, the tube 202 is manufactured in accordance with manufacturingsteps including a material kneading step, a tube material extrusionmolding step, a cutting step, an air valve mounting step, a piecingstep, a joining step, a first vulcanizing step, a sealant filling step,a raw rubber sheet sticking step, a second vulcanizing step, and aninspection step.

First, a raw rubber kneaded at the material kneading step isextrusion-molded at the tube material extrusion molding step, to form atube material 202′ made of the raw rubber. The tube material 202′ iscontinuously extrusion-molded from a nozzle of an extrusion moldingmachine and includes a peripheral wall 204 formed in a circular shape intransverse cross section and a bulkhead 205 connecting two pointspositioned along the diameter of the peripheral wall 204. The peripheralwall 204 is divided into an air chamber side peripheral wall 204 i and asealant chamber side peripheral wall 204 o with respect to the portionsconnected to the bulkhead 205.

The tube material 202′ is cut into a specified length at the subsequentcutting step, and an air valve 206 is mounted at a suitable position onthe air chamber side peripheral wall 204 i at the air valve mountingstep. At the piercing step, the sealant chamber side peripheral wall 204o of the tube material 202′ is pierced to form sealant filling holes 204₁, . . . , 204 ₁.

Both the end portions of the tube material 202′ are joined to each otherat the subsequent joining step, and at the first vulcanizing step, thetube material 202′ is inserted in a heating die, and the air chamberside peripheral wall 204 i and the sealant chamber side peripheralchamber 204 o are brought in close contact with the heating die and thebulkhead 205 is also brought in close contact with the sealant chamberside peripheral wall 204 o by supplying a heated air or a hightemperature steam into the air chamber 203 from the air valve 206. Insuch a state, vulcanization is performed by heating the heating die.

At the subsequent sealant filling step, the sealant 8 is supplied fromthe sealant filling holes 204 ₂, . . . , 204 ₁ to fill the sealantchamber 207. At this time, by expanding the air chamber 203 by a supplyof from the air valve 206 prior to the filling of the sealant 208, thebulkhead 205 is brought in close-contact with the sealant chamber sideperipheral wall 204 o to perfectly discharge the air in the sealantchamber 207. In such a state, the filling of the sealant 208 is started.The starting of the filling of the sealant 208 in the state wherein theair in the sealant chamber 207 is perfectly discharged, it is possibleto effectively prevent the entrapment of the air in the sealant 208 andhence to fill the sealant chamber 207 with only the sealant 208.Additionally, since the air is supplied into the air chamber 203 usingthe air valve 206, it is possible to eliminate the need for theprovision of an air filling hole in the air chamber side peripheral wall204 i.

A raw rubber sheet 219 is stuck on the peripheral wall 204 so as tocover the sealant filling holes 204 ₁, . . . , 204 ₁ at the raw rubbersheet sticking step, and then the sealant filling holes 204 ₁, . . . ,204 ₁ are blocked by local vulcanization of the vicinity of the rawrubber sheet 219 at the second vulcanization step, to finish the tube202. Since the sealant filling holes 204 ₁, . . . , 204 ₁ are blockedusing the raw rubber sheet 219 being the same material as that of thetube material 202′, it is possible to improve the strength of theblocking portion, and hence to effectively prevent the leakage of thesealant 208. Thus, the finished tube 202 is inspected at the inspectionstep, to complete the manufacturing steps.

Next, the function of the embodiment will be described. As shown in FIG.11, when the tube tire T rides over an obstacle 220 on a road surfaceand is applied with a shock load, part of the tire 201 and the tube 202are compressed in the radial direction by the load. At this time, thetire 201 and the tube 202 are clamped between the flange portions 212,212 of the rim R projecting radially outward and the obstacle 220.However, since the elastic mousse 216 is interposed between the tire 201and the tube 202, the load applied to the tube 202 is dispersed andreduced, to thereby effectively prevent damage of the tube 202 due torim striking.

FIGS. 12(a) to 12(c) are views illustrating the function of the tubetire T in this embodiment on the assumption that the tube tire T has nomousse 216. FIG. 12(a) shows a state in which the tube 202 is mounted inthe tire 201 and the air chamber 203 is not yet filled with air, thatis, a tube free state in which the tube 202 is not expanded. In such astate, a gap is present between the outer surface of the tube 202 andthe inner surface of the tire 201. FIG. 12(b) shows a tube expandedstate in which the air chamber 203 of the tube 202 is filled with an airthrough the air valve 206. In such a state, the outer surface of thetube 202 is brought in close-contact with the inner surface of the tire201 by expansion of the air chamber 203, with a result that the gapdisappears.

Incidentally, when the tube 202 in the tube free state is inserted fromthe opening of the tire 201, if the tube 202 is a small-size, it can beeasily inserted. However, with respect to such a small-size tube 202, asectional expansion ratio R of the tube 202 is required to be set at alarge value for the purpose of bringing the outer surface of the tube202 in close-contact with the inner surface of the tire 201 by expandingthe tube 202 in the tire 201. The sectional expansion ratio R is givenby an equation of R=B/A, where A is a cross section of the tube 202 inthe tube free state [area of a hatching portion in FIG. 12(a)], and B isa cross section of the tube 202 in the tube expanded state [area B of ahatching portion in FIG. 12(b)].

When the sectional expansion ratio R is set at a large value asdescribed above, the tension of the bulkhead 205 of the tube 202 becomeslarger upon expansion of the tube 202, and the bulkhead 205 is appliedwith loads which are directed toward the tube free state by itselasticity as shown by arrows f of FIG. 12(b).

As shown in FIG. 12(c), in the case where the sealant chamber 207 ispierced at two positions a, b by nails or the like penetrating the tire201 and the tube 202, if the wheel is in a rotating state, the bulkhead205 is biased on the sealant chamber 207 side by a centrifugal force toprevent the air in the air chamber 203 from flowing into the sealantchamber 207 through the pierced portion b. However, if the wheel isstopped in rotation and the centrifugal force disappears, the bulkhead205 applied with a large tension is contracted on the air chamber 203side, so that the air in the air chamber 203 flows into the sealantchamber 207 and is mixed with the sealant 208. The sealant 208 thusmixed with the air is obstructed from reaching the pierced portions a,b, or it is made poor in flowability, resulting in a degraded sealingperformance thereof.

In the tube tire T in this embodiment, however, since the tube 202 inthe tube free state is inserted in the mousse 216 previously mounted inthe tire 201 and then expanded, it is possible to reduce the sectionalexpansion ratio R of the tube 202 and hence to solve the above-describedinconvenience. The reason for this is that since the mousse 216 iselastically deformed more easily than the tire 201, if the dimension ofthe tube 202 in the tube free state is set at a large value, the tube202 in the tube free state can be easily inserted in the mousse 216 byelastically deforming the opening of the mousse 216. As a result, sincethe dimension of the tube 202 in the tube free state can be thus set ata large value, the expanded amount, that is, the sectional expansionratio R of the tube 202 can be reduced.

According to the present invention, the tube tire includes a tube havinga peripheral wall formed in a circular shape in cross section, whereinthe interior of the peripheral wall is partitioned by the bulkhead sothat the air chamber to be filled with air is defined between the airchamber side peripheral wall constituting a half circumference of theperipheral wall and the bulkhead and the sealant chamber to be filledwith a sealant is defined between the sealant chamber side peripheralwall constituting the remaining half circumference of said peripheralwall and the bulkhead.

Accordingly, even when the tube is pierced by a nail or the likepenetrating the tire, the pierced portion can be immediately repairedwith the sealant to thereby prevent the leakage of an air from the airchamber. Further, according to the present invention, since the bufferis interposed between the tire and the tube, a nail or the like piercedin the tire does not easily reach the tube by the presence of thebuffer, and also even when the tube is forcibly clamped between the tireand the tube by the rim striking phenomenon, a load applied with thetube can be reduced by the effect of the buffer, to thereby prevent thegeneration of shock puncture. Also, if the air in the air chamber leaksfrom the air chamber due to damage to the tube, since the outer shape ofthe tire can be maintained by the rigidity of the buffer, the operationof the wheel can be continued until a repair shop is located.Additionally, a large-size tube can be assembled in the bufferpreviously mounted in the tire because the buffer is elasticallydeformed. This is effective to reduce the sectional expansion ratio ofthe tube, and hence to enhance the sealing performance of the sealant.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A tube for a tire, the tire including an outerground engaging portion, a pair of sidewalls integrally formed toopposite sides of the outer ground engaging portion and extendingradially inward, and radially inner first and second edges of thesidewalls being adapted to abut against first and second rim flanges ofa wheel, said tube comprising: walls forming a toroidal shape with aninner radius, a central radius, and an outer radius, said tube beingadapted to fit inside a space formed between the sidewalls and adjacentto a radial underside of the ground engaging portion, said walls of saidtube having a wall thickness which is substantially uniform; and a firstreinforced member positioned along a first circumferential strip of saidwalls of said tube located between said inner radius and said centralradius, said first reinforced member creating an overall tube thicknessacross said first circumferential strip, wherein said first reinforcedmember rises from said wall thickness to an increased thickness and thendeclines to said wall thickness, and wherein said first reinforcedmember is positioned on said walls so that when the ground engagingportion of the tire deforms toward the radially inner first edge of thesidewalls, said first reinforced member will overlay the first rimflange of the wheel; and a second reinforced member positioned along asecond circumferential strip of said walls of said tube located betweensaid inner radius and said central radius and opposite to said firstcircumferential strip, said second reinforced member creating an overalltube thickness across said second circumferential strip, wherein saidsecond reinforced member rises from said wall thickness to saidincreased thickness and then declines to said wall thickness, andwherein said second reinforced member is positioned on said walls sothat when the ground engaging portion of the tire deforms toward theradially inner second edge of the sidewalls, said second reinforcedmember will overlay the second rim flange of the wheel.
 2. The tubeaccording to claim 1, wherein said first reinforced member is integrallyformed with said walls of said tube along said first circumferentialstrip, and said second reinforced member is integrally formed with saidwalls of said tube along said second circumferential strip.
 3. The tubeaccording to claim 1, wherein said first reinforced member protrudesfrom an inner surface of said walls of said tube along said firstcircumferential strip, and said second reinforced member protrudes fromsaid inner surface of said walls of said tube along said secondcircumferential strip.
 4. The tube according to claim 3, wherein saidfirst reinforced member is integrally formed with said walls of saidtube along said first circumferential strip, and said second reinforcedmember is integrally formed with said walls of said tube along saidsecond circumferential strip.
 5. The tube according to claim 1, whereinsaid walls of said tube are formed of rubber and said first and secondreinforced members are formed of rubber.
 6. The tube according to claim1, further comprising: a first chamber formed between said firstreinforced member and said walls of said tube; and a second chamberformed between said second reinforced member and said walls of saidtube.
 7. The tube according to claim 6, further comprising: a sealantcontained inside said first and second chambers.
 8. The tube accordingto claim 1, wherein said first reinforced member protrudes from an outersurface of said walls of said tube along said first circumferentialstrip, and said second reinforced member protrudes from said outersurface of said walls of said tube along said second circumferentialstrip.
 9. The tube according to claim 8, wherein said first reinforcedmember is integrally formed with said walls of said tube along saidfirst circumferential strip, and said second reinforced member isintegrally formed with said walls of said tube along said secondcircumferential strip.
 10. The tube according to claim 1, furthercomprising: a first bulkhead wall connected to said walls of said tube,adjacent to the radial underside of the ground engaging portion of thetire, said first bulkhead wall forming a first bulkhead chamber withsaid walls of said tube, which covers substantially all said walls ofsaid tube located adjacent the underside of the ground engaging portionof the tire; and a sealant contained inside first bulkhead chamber.